It is known to provide bearings with dedicated lubrication systems in order to extend their service life and increase their rotation speed. This technique is in particular used in turbochargers, where high rotation speeds are involved. These lubrication systems often include ducts extending through the outer ring of the bearing in order to allow passage of oil, or more generally lubricant, in the inside of the bearing in order to facilitate the relative rotation of the inner and outer rings. The lubricant is injected with pressure, from ducts provided in a housing in which the bearing is mounted, through the lubrication ducts of the outer ring.
Lubricant injection techniques known, for example, from US-A-2008/098735, use lubricant injection ducts which are perpendicular to the rotation axis of the bearing and enter in the interior of the bearing along a purely radial direction perpendicular with respect to the rotation axis of the inner ring. This technique causes bad lubricant reparation and can lead to solid deposits in case the lubricant reaches high temperatures. Moreover, the radial injection of oil creates a resistive torque exerted against the rotation of the inner ring.